The objective was to determine the relationship between family functioning and adolescent pregnancy in the city of San Lorenzo 2014. The methodology was quantitative, not experimental, descriptive, correlational and cross; involving 75 pregnant adolescents between 12 and 19 years of the city of San Lorenzo. The information was collected using as technical survey and interview and questionnaire as a tool Modified Family APGAR. Data analysis was done using the Statistical Package for Excel and SPSS22. The results were that 100% (75) of pregnant adolescents 89% (67) showed some degree of family dysfunction, family dysfunction within this the most representative mild family dysfunction was 46% (35). Regarding the stages of adolescence who identified the highest percentage 52% (39) were found in the stage of late adolescence. Researching family dysfunction per basic function is resulting in Adaptation 87% (65) showed some degree of family dysfunctionality of which the majority with 47% (35) is mild; Venture 92% (69) had dysfunctional families, of which 40% (30) was mild and 40% moderate; to gain 91% (68) had dysfunctional families, of which 44% (33) was mild. Regarding Affection 93% (70) had family dysfunction; within which 57% (43) was mild. Finally Resources 81% (61) showed some degree of family dysfunction, of which 47% (35) was mild. Conclusions: According to the family APGAR test modified most pregnant teenagers presented family dysfunction of some sort, which was found in the five basic functions evaluated to be more mild family dysfunction. Of the five basic functions evaluated Affection had greater dysfunction. There is a statistically significant relationship between family functioning and adolescent pregnancy in Adaptation Functions 95%, 90% and Affection Gain 90%.